How does blackmail work in RE?

[captainpatch]

I keep on getting messages about some extortionist demanding Big Bucks or he will sabotage one of my businesses. I have been going on the supposition that the consequence would be that one of my businesses of the type specified by the blackmailer would lose one level of productivity. Knocking a Level 3 business down to a Level 2 business for example. Given that going from Level 2 to Level 3 can cost around 1 million dollars, paying $300,000 in blackmail seems more cost effective. Bbbbuuuttt.....

Is the damage threatened by the blackmailer an absolute given? One of those businesses stated by the blackmailer WILL lose a level productivity if the blackmail isn't paid?

IS IT (just) ONE level of productivity being lost? Could it lose two or more levels?

Is the damage permanent? Or, like a Sabotaged Terminal or Industry, does it repair itself with time?

Is there any way at all to defend against blackmail? Any way at all?

Does paying a blackmailer increase or decrease the _frequency_ that blackmail threats get thrown at you? ["That was easy money! Let's do it again!" Or, "He NEVER pays the blackmail. We shouldn't even waste our time."]

^Those questions should do for starters.